@Admin
“In other words, make sure that pre_site_transient_update_plugins always equals null so that plugin updates will never be displayed”
You out geeked me with that comment.
I also fixed some of the errors.
I had Ithemes (Better WP Security) deactivated but had to completely delete it.
Also deleted Member player a 3rd party video player.
The error went away on 6 sites, Only have 1 site that is picky.
On the picky site I installed a random plugin from WP repo and the BPS Pro update appeared.
Though I still get the transient_update error on Manual upgrade check.
Is their a PhpMyAdmin command to clear the transient update plugin??
TUTORIAL:
If you get a “Error: Unable to delete the _site_transient_update_plugins option value from your database”
while running “Manual Plugin Upgrade” from WP Plugins Page or “Force A Plugin Update Check” from Pro Tools.
It might mean that a 3rd party plugin or a WP repo plugin is blocking that function. To fix the issue read below.
Use BPS Pro Pro-Tools – “String Finder” tool (not the DB String Finder tool).
search string: site_transient_update_plugins
Search path: YOURPATH\public_html\wp-content\plugins\
*deactivating plugins may not be enough so you have to delete them. Also try to install another plugin to see if BPS Pro update appears.
Delete plugins one by one. After delete, run “Manual Plugin Upgrade” from WP Plugins Page or “Force A Plugin Update Check” from Pro Tools.
If it works, go to Plugins Page and refresh browser and look out for the “Upgrade” link.
You might have to refresh browser more than once till the Upgrade appears.